Random thoughts on policy for technology and on technology for policy

I am a big fan of open underlining as a form of taste-sharing and low-cost collaboration.
Some time ago I tweeted an idea which got some positive feedback:
“I need an app that tweets whatever I underline on a pdf. Just as we do for good sentences at conferences”
While I am reading and studying material, I sometimes find a gem and my first instinctive reaction is to tweet it.
I would love to to this in an easy way, and I am sure it wouldn’t be difficult. Yet I know no app for this.
Ideally, it would link to the original source, enable tagging or hashtagging. It would work on any document, pdf and webpage. It would merge twitter, pdf reader and online highlighters.
Imagine: after a few people start to use it, it would become an unbelievable treasure of knowledge – even more if linked to eReaders (currently Kindle does not allow pdf annotation). You could also be connected to people who underlined the same lines as you – which I find an amazingly effective way to connect.
Plus, the most important thing is that I have a name for this 🙂 . Tweetlining.
I really hope some developers out there is able to do it. Please. I suggested that Mendeley could to it but is there anything out there already?